<?php
namespace User\Controller;
use Think\Controller;
class BaseController extends Controller {
    public $session_id;
    /*
     * 初始化操作
     */
    public function _initialize() {  
    	$this->session_id = session_id(); // 当前的 session_id
        define('SESSION_ID',$this->session_id); //将当前的session_id保存为常量，供其它方法调用 
    }
}